Use nc command if it exists and specify explicit connection timeout to avoid hanging

[vpriscan]

Use nc command if it exists.

Add explicit connection timeout of 10 seconds, because, depending on the system, nc command could be a symlink to netcat or Ncat program (a netcat re-implementation), and Ncat has a default connection timeout od 10 seconds (thus this value was chosen), while netcat has infinite connection timeout by default. Infinite connection timeout resulted in wait-for-it.sh to hang and never succeed to connect to target host if it wasn't reachable initially but became reachable a bit later (for example when starting docker containers), until main wait-for-it.sh timeout expired, at which point it is too late.

The same timeout value of 10 seconds is also added to network redirection for the same reason.